Results 1 to 3 of 3

Thread: Difference between tablespace creations

  1. #1
    Contributing Member
    Join Date
    May 2006
    Answers
    64

    Question Difference between tablespace creations

    While creating tablespace is there any difference in creating it using default dictionary management and by creating tablespace using local management mode provided both have same size, place of storage and so on. If so what is the difference?


  2. #2
    Expert Member
    Join Date
    Sep 2006
    Answers
    130

    Re: Difference between tablespace creations

    Hi,

    Since there is no response for this post for a long time, I thought of replying for the above query regarding tablespace.


    When Oracle allocates space to a segment (like a table or index), a group of contiguous free blocks, called an extent, is added to the segment.
    Considering the extent allocation, the tablespace is created with Default dictionary tablespace or Locally managed tablespace.
    These are the two different methods for Oracle to keep track of free and allocated extents.

    Tablespaces that record extent allocation in the dictionary, are called Dictionary managed Tablespaces
    Oracle uses the data dictionary (tables in the SYS schema) to track allocated and free extents for tablespaces that is in "dictionary managed" mode.

    Tablespaces that record extent allocation in the tablespace header, are called Locally managed Tablespaces.
    In Locally managed tablespace, each tablespace manages it's own free and used space within a bitmap structure stored in one of the tablespace's data files.
    Each bit within this bitmap determines if a corresponding extent in the tablespace is free or used.
    There are two main advantages of Locally managed tablespaces:
    1. Recursive Space Management is avoided
    2. Adjacent free space is automatically coalesced.

    Hopefully its clear :-)

    *** Innila ***

  3. #3
    hemant.agarwal03
    Guest

    Re: Difference between tablespace creations

    If we use dictionary manage table space it's increase our recursive space management. and extra burden on data_dictionary tables.


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
About us
Applying for a job can be a stressful and frustrating experience, especially for someone who has never done it before. Considering that you are competing for the position with a at least a dozen other applicants, it is imperative that you thoroughly prepare for the job interview, in order to stand a good chance of getting hired. That's where GeekInterview can help.
Interact